I never pay more than 5€ for any bottle, and usually get them for much, much less. Last Sunday I bought 3 for 1€ and got an extra Garden Girl Yellow cap because the lady at the stall had just broken the bottle and didn't have any use for it. :)

Avon started making these bottles in the early 70s, and people started collecting them as an investment. Then Avon flooded the market. Now you can get them for as much as $20-$30 for a bottle in perfect condition, full and in it's original box; or as low as a few for a dollar, if they are less than pristine. Mine are all in good condition, but the plastic Avon used for the toppers usually turns an ugly yellow, so I am always on the lookout for extras.
Avon sometimes reissued the same figurine with different colors from one year to the next.